Summer Weather – The Enemy of Your Tires?
August 18th, 2015
Let’s talk for a moment about tire pressure.
Every tire flexes a little at the bottom, as the weight of the vehicle bears down on it. The section that is subject to that weight and flexing changes constantly as the tire rotates, and the average tire rotates 750 times over the course of a mile. At 60 mph, that means the tire rotates 750 times per minute. All that flexing and deformation means heat buildup, and increases tire pressure by roughly four pounds per square inch (PSI). After an hour or so on the road, a tire is about 50 degrees hotter than ambient air…but that temperature differential is even greater in hot weather, especially since pavement is hotter than ambient air. Heavier loads and higher speeds will add to that heat buildup.
Now, consider that a tire that’s low on air will build up even more heat, due to more flexing and deformation…which translates to more rolling resistance and friction to get the vehicle down the road. That’s not even thinking about the extra gas that’s used to keep those tires rolling. Think about what it’s like to ride a bicycle with underinflated tires; a bit like trying to ride through wet sand. Eventually, that flexing, deformation and heat will destroy a tire altogether as its internal structure and steel/nylon belts break down and it starts to throw off chunks of tread, like the strips of 18-wheeler tires that litter the shoulders of interstates.
Cars built since 2008 all feature a Tire Pressure Monitoring System (TPMS), which alerts you when a tire is low; by that time, though, at least one tire is low enough to compromise handling, safety and fuel economy. So, what are your options to ensure tire safety in the summer months? Schedule regular appointments for wheel alignments and tire rotations to keep tires in top shape!
• Check your tire pressure often, especially before a long trip. Once a week is a good rule of thumb.
• Get a good-quality tire gauge. Pencil-style gauges aren’t very accurate, nor are the built-in ones on gas stations’ air hoses. A dial-type gauge or digital gauge are both better choices.
• Remember that air pressure increases with heat from highway driving; be sure to check air pressure when the tires are still cold. On most vehicles, you can find the correct air pressure specs on a placard or sticker attached to the frame of the driver’s door.
• Bear in mind that the weight of several passengers, luggage and a full tank of gas puts more stress on tires, as does towing a trailer.
• Tires that are already worn are much more susceptible to damage and eventual failure from heat buildup in summer heat. Check your tires regularly for signs of uneven or excessive tread wear, and have them rotated at every oil change.
Posted in: Tire 101